According to the documentation, ``EntityManager::find`` should return one entity given it's primary key. When a primary key of an entity is composed of multiple associations, one (me ) would expect that the following works, but it doesn't:
```php
$entity = $_em->find('My\EntityClass', array(
'assoc1' => $instance1,
'assoc2' => $instance2
));
PHP Fatal error: Object of class My\EntityClass could not be converted to string
```
The only working way I've found is the following:
```php
$entity = $_em->find('My\EntityClass', array(
'assoc1' => $instance1->getId(),
'assoc2' => $instance2->getId()
));
```
I think that this second scenario is not correct, since expose implementation details.